The cause for last week's Soyuz rocket failure that crashed Russia's Progress 44 supply ship heading to the International Space Station has been identified, said Russian news reports.

According to Russian Federal Space Agency (Roscosmos) spokesman Alexei Kuznetsov, it was a malfunction in the gas generator in the Soyuz carrier rocket's third stage engine that caused the robotic Progress 44 cargo ship accident on Aug. 24.

According to preliminary information, during the launch of a Soyuz-U carrier rocket with a Progress M-12M transport ship aboard on August 24, the engine malfunctioned in the third stage on the 325th second, which resulted in its emergency deactivation, Kuznetsov told Itar-Tass News Agency.

Earlier a source in rocket and space industry revealed that a drop in pressure in the fuel tanks was registered after 350 seconds of the flight, and after some time contact with the spacecraft was lost. The Mission Control Centre, however, didn't comment on the information, Itar-Tass reported.

The unmanned ISS Progress 44 launched from the Baikonur Cosmodrome at 9 a.m. EDT (7 p.m. Kazakhstan time) Aug. 24 on a Soyuz U rocket, bound for the ISS. At 5 minutes and 25 seconds into flight, the Soyuz rocket, which was carrying about 3 tons of supplies to ISS experienced a third-stage engine shutdown due to an anomaly and crashed in Siberia.

NASA said on Monday that it is considering plans to pull astronauts off the $100 billion orbiting research facility if the Russians could not determine and fix the problem before the last of the present residents are scheduled to leave by mid-November. The agency further added that until the problem has been resolved completely, there won't be any manned Soyuz rocket lifting off. Hence, the chances of leaving the space station unmanned are still alive.

Meanwhile, Russian officials are looking for debris from the fall area in the Altai region's mountains. Up till now, the Federal Space Agency has been using only one Mi-8 helicopter, which belongs to the local Emergencies Ministry. However, more aircraft will be deployed to conduct the search.

The ISS is operated by Expedition crews and has been continuously staffed since November 2000 - an uninterrupted human presence in space for the past 10 years and 300 days. As of June 2011, the crew of Expedition 28 is aboard.

If NASA decides to evacuate ISS, it can do that as most of its functions can be controlled from the ground itself. But, there is always a risk of anomaly or any component malfunction with no astronauts available on orbit to fix it.